Abstract: At present，extended-reach well（ERW）drilling has become an important means for oil and gas exploration and development，and trajectory design optimization is the key to the successful drilling of ERW and the improvement of operating efficiency. With the continuous increase in horizontal displacement and horizontal length to vertical depth ratio，ERW drilling is facing many serious challenges. Therefore，it is necessary to comprehensively analyze and evaluate the factors affecting trajectory design，such as trajectory control ability and wellbore stability，so as to form an integrated technical thinking. In this study，a matrix of trajectory evaluation indicators was first established by analyzing the characteristics of ERW drilling technique，and then scores and weights of all indicators were determined based on expert experience. Consequently，quantitative evaluation was used to judge the selection of ERW trajectory，and applied to the ERW design in an oilfield. Drilling operations were carried out in the field strictly following the selected trajectory plan，and finally a high-quality trajectory was achieved for the whole well. The results show that the evaluation method is practicable and feasible，and provides a technical basis and guiding method for selecting the design plan of ERW trajectory.

Key words: extended-reach well（ERW）；quantitative evaluation method, trajectory optimization, evaluation indicators, weight

摘要： 大位移井钻井已成为目前油气勘探开发的重要手段，轨迹设计优化是大位移井钻井作业成功与提高作业效率的关键。随着水平位移和水垂比的不断增加，大位移井钻井面临着许多严峻挑战，因此需对轨迹控制能力、井壁稳定性状况等影响轨迹设计的因素进行综合分析与评价，形成一体化的技术思考。通过分析大位移井钻井技术特点建立轨迹评价指标矩阵，依据专家经验确定各评价指标得分与权重，从而采用定量评价进行大位移井轨迹优选评判，并在某油田大位移井设计中得到了应用。现场严格按照优选出的迹方案进行钻井作业，最终实现了全井井眼轨迹质量优质，结果表明该评价方法切实可行，为大位移井轨迹设计方案优选提供了技术依据与指导方法。

关键词: 大位移井, 定量评价方法, 轨迹优化, 评价指标, 权重